Billing records filed with the court show the examiner is investigating an issue that has angered many of Lehman's creditors: how the Federal Reserve and the New York Fed -- which lent Lehman $46 billion in cash and securities before its bankruptcy filing last September -- were paid promptly and in full, while tens of billions of dollars in other debts were left to be sorted out in court. It remains unclear when and how much Lehman creditors will be repaid.

The pursuit of this story would push bankruptcy law into basically uncharted territory, notes, the article, and could have significant ramifications on future bailouts. If the Fed can't presume preferential treatment in getting paid back, it's likely to be much more gun-shy about who it loans out to, lest it risk its own insolvency.

If nothing else, this is more unwanted attention for the Fed. Expect its Congressional critics, who are already pushing for an audit, to jump all over this one.

More background:

Preference claims attempt to claw back assets a company moved shortly before filing for Chapter 11, said Cravath's Mr. Levin. Such moves, if made within 90 days of a bankruptcy filing, are deemed to "prefer" one creditor over others. The bankruptcy code dictates that such value should be moved back to the bankruptcy estate, to be shared among all creditors.

Billing records for Jenner & Block and its financial adviser Duff & Phelps, make numerous references to investigating "possible claims against Federal Government," the Federal Reserve and the New York. Fed. Most of that research relates to "avoidance" claims.

Jenner & Block said that on May 18 it "reviewed background material re possible claims against Federal Government."